Separation Clause - Notice Period

Hello everybody,
Would like to hear from you all on separation clause.
Read in one of the employment contract under separation section :
That if the employees resigns from the services needs to serve 03months notice period and if company terminates an employee will give 01 month notice period or salary in lieu.
Wanted to check the legality of the clause.
Regards
Anjali Sarin

Mr. Kumar,
Does that mean that if an employee agrees to the contract then it is lawful? or if the employee disagrees with the clause, then?